Asking is a courtesy, it’s polite, and I get angry when someone doesn’t. It angers me even more when they think that I’m annoyed at them for actually doing it. I tell them that all they had to do was ask and I would have said yes, but they just should have asked first. I guess some people just don’t grasp this concept- like if I was going to say yes anyway then what’s the problem? The problem is it’s rude and then I don’t know or there might have been other circumstances like “yes you can borrow that but I need it back by such and such” or “yes you can have a cookie but not too many please I’m saving them for something” rather than just thinking they are entitled to eat all the cookies because I “would have said yes”. If I’m going to say no there is a reason for it, so of course it would be hard to forgive them after the fact. I’d rather just be honest and tell them why I don’t give them permission this time, then hopefully they would understand rather than everyone getting hurt and angry afterwards.
edit :: However, there are other circumstances which might be better just to go for it and ask permission later. Maybe the person you need to ask just doesn’t understand and you’ll know that they would say no and rather than raising suspicion and making it harder for yourself to do what you want, just do it without them knowing and then they’ll see that it really was best for you. Like I dunno… a teenager wants to play a sport and their parents think they should be studying all the time but really playing sport would make them happier and more energetic and help their brain to learn better anyway so it’s a win win, but maybe you don’t tell them until after you’ve joined and can show them the results.
This is an exception though- not the rule, to me, and it really really depends on the circumstance.